Keyhole plug for cylinder locks



Sept. 17, 1929.

S. SUNDEL KEYHOLE PLUG FOR CYLINDER LOCKS Filed Sept. 29, 1925 WITNESSES Q I I Tia. :1

INVENTOR ATTORNEYS Patented Sept. 17, 1929 l '1 I I warren srAies PATENT'O'IFFIICEIQI7' SAMUEL 'SUNDEL, on NEW HAVEN, oonnno'rrcur, Ass/xenon or ONEHALF 'ro Lnon LAUTERVIOFNEW Yemen. Y. a i I KEYHOLEIPLUGTFO/R CYLINDER LOCKS Application filed September 29, 1925. Serial No. 59,345.

This invention relates to keyhole plugs for 3 represents a cylinder lock of ordinary cylinder locks, an object of the invention beor standard construction. I Such a lock is proing to provideya plug which can be inserted vid'ed'withsectionalpin tumblers 4, pressed in a cylinder lock, which Willprevent the use by springs 5 into locking engagement with a a 5 of the ordinary key to operate the lock, and I rotary barrel 6. This barrel has a keyholefw 55 which cannot be removed except by the infor the reception of a key (not shown) which sertion of a plug key. t functions to properly register the pin tum- An object of the invention therefore is to blers and allow the barrel to be turned. provide a plug wliichcan be inserted in the To prevent theuse of the ordinary key or lock and which will prevent the operation skeleton key I provide my improved plugvl 60 of the look even though the user has the Which is adapted to be inserted into the key-f proper key forthelock or a master key. The 19 slot or g'roove 7 of the lock and has a uses for such a plug are many. For example, fixed disk or plate 8 at its outer end Which where a salesman has on display in a hotel bears against the face of the lock and which I room valuable articles, he can use such a plug has an opening 9 therein of proper shape to 65 to prevent the employees or tenants of the receive the plug key 2., I hotel from entering the room. F urthcrmore, This plug 1 ismade of proper shape in cross a plug of this kind can he used in automobile section to fit the key receiving groove or slot locks, which will greatly overcome the liabil- 7 and at its inner end is formed Wi an upity of theft of the car. Also it is to be under- Wardly projecting tongue. 10 h ving an in- 70, stood that the invention can be applied to any clined or cam face 11 which functions to force cylinder lock for any use to which it may be the pin tumblers aupwardly when the plug put. 1 is inserted in the lock. As this tongue 10 I With these and other objects in view, the passes the tumblers 4, the latter willmove invention consists in certain novel features of downwardly into the path of the tongueand 7 construct-ion and combinations and arrangep event the removal of he plug, as clearly ments of parts, which will be more fully hereillustrated in Figure 1. p I I k a Q, inafter described and pointed out in the In order to remove the plug it is necessary claims. to employ the proper plug key 2, as shown in p In the accompanying drawingsperspective in Figure 4. l

Figure 1 is a view in longitudinal section The plug key 2 has a longitudinal shank through a cylinder lock showing my importion 12 and a finger manipulating porproved plug in operative position therein; tion 13 at its outer-end. The shank 12 has a Figure 2 is a similar view showing the plug straight upper edge 14 and a beveled or ta key in position for removal of the plug; poring end 15 which constitutes a cam and Figures 3 and 4; are perspective views of which when the key 2 is in'sertedfunctions the plug and the plug key, respectively to lift all of the tumblersl and support them. Figure 5 is a view in transverse section The shank 12 on itslower' edge at its forthrough the registering plug and plug key, ward portion'is recessed as shown at 16 so as L the section being taken on the line 55 of to accommodate a raised portion 17 on the Figure 2; upper edge of the plug 1 and allow the shoul- Figure 6 is an end view of a cylinder lock ders 18 and 19 on the key 2 and plug l respecshowing my improved plug in operative potively, to engage each other, so that when the" sition therein. key is withdrawn it will carry the plug 45 My invention includes the provision of a with it. p a a r j,

plug 1 and a plug key 2. I employ this term The proportions of these shoulders are plug key to distinguish it from the ordinary somewhat exaggerated for purposes of clearkey designed to operate the lock as the plug ness as only a slight engagement is necessary; key is only used for removing the plug and and also some slight freedomo't movement is p 50 is in no sense designed for operating the lock. necessary for the key to fall into locking engagement with the plug, but this is very slight, and hence for clearness of illustration the proportions and sizes are somewhat ex- 1 aggerated, but it is of course to be understood that there is a sufficient space for the free entrance of the key to allow it to fall into interlocking engagement with the plug.

\Vhile I have illustrated in Figure 1' a plug of a length which will so position the tongue 10 as to supportone of the tumblers 4 it is obvious that this tongue may be proportioned longitudinally of the plug so that it may support any desired number or none of the plugs and by varying the lengthof the web portion 17 and corresponding length of the shoulder portion 18 of the key a greatnumber ofidifferent combinations of plug and key can be provided so that each owner of a plug and key may be protected from unauthorized operation.

When it is desired to securethe lock, the operator merely forces theplug into position, as indicated in Figure 1. This plug cannot be'removed except by the use of the proper plug key 2, and it will prevent the use of the ordinary key or master key and will prevent the operation of the lock except by the holder of the proper plug key, who must first insert the same and remove the plug before the ordinary key can be used.

Various slight changes and alterations might be made in the general form of the parts described without departing from the invention, and hence I do not limit myself to the precise details set forth but consider my Y self at liberty to make such slight changesand alterations as fairly fall within the spirit and scope of .the appended claims.

I claim: H

1. A key devicefor use in connection with locks employing tumblers comprising a plug part adapted to be inserted into the key aperture of the lock, said part having a projection adapted to cooperate with a predetermined number of tumblers of the lock to prevent withdrawal or removal of said part and the other part being adapted to interlock with the first named part and to permit the removal of said part, a disk on the outer end of the plug parthaving an opening adapted to receive the said other part.

Q A plug'key of the class described com prislnga-part adapted to be insertedinto a,

lock employing tumblers and retained against displacement therefrom by a predetermined number of said tumblers and including another part adapted to be inserted into the lock and to cooperate with said first named part and said tumblers to permit withdrawal thereof, a member formed at the outer part of said first part adapted to abut the outer face of said lock and retain said part against. predetermined displacement inwardly into said lock, said member also serving to guideand limit the insertion of said second part into said lock aperture.

3. A plug key of the class described com-V with the contour of the key aperture of the i look, a member disposed on the outer end of said first part adapted to cover the lock opening and including an opening corresponding in cross section to said second part of said plug key.

4. A plug key for tumbler locks,said key being composed of two interlocking parts, both of which when placed one upon the other and edge toedge, cooperatively are of a cross section corresponding with the key aperture of a predetermined lock, one of said parts comprising the plug part, said plug part being provided with a member on the outer end thereof to limit the insertion thereof into the opening of the lock, said member being formed with an opening to limit the insertion only of the other of said cooperative parts.

SAMUEL SUNDEL. 

